This is actually a common question. You pay the shipping cost based on the total weight of the package including the packaging. If you ship a 1 pound item in a 5 pound box then you’re going to pay shipping on 6 pounds. If you shipped the 1 pound item in a 2 ounce envelope then you’re going to pay postage on 1 pound 2 ounces. Thus, using the lightest packaging available will be cheaper. Remember how USPS rates work. There is no difference in cost between a package that weighs 2lbs 1 ounce and 3 pounds even, but there is a significant increase in cost between 3 lbs even and 3lbs 1 ounce. Likewise, there is no difference in cost between a package that weighs 1 pound 1 ounce and 2 pounds even but there is a significant increase between 2 pounds even and 2 pounds 1 ounce. This means that your packaging can weigh as much as 15 ounces and not cost any more to ship than if you had put a shipping label on the item itself. Take into consideration whether or not the item is fragile when considering packaging options. Many of the USPS boxes are durable and lightweight. You can order USPS Priority Mail boxes and have them delivered for free at The USPS Store. They are also available for free at any Post Office and most other mailing stores.